1. Palmero, I. & Peters, G. Cancer Surv. 27, 351–367 (1996).
2. Pomerantz, J.et al. Cell 92, 713–723 (1998).
3. Zhang, Y., Xiong, Y. & Yarbrough, W. G. Cell 92, 725–734 (1998).
4. Stott, F. et al. EMBO J. (in the press).
5. Kamijo, T.et al. Proc. Natl Acad. Sci. USA 95, 8292–8297 (1998).